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Патент USA US3025589

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March 20, 1962
3,025,579
G. LITTLEWOOD
CONTINUOUS CASTING OF METALS
Filed June 16, 1959
INVENTOR.
BY
Geoffrey Li’t?ewood
ATTO RNEY
United States Patent O?fice
1
3,025,579
Patented Mar. 20, 1962
2
magnetic valve 25 in a second delivery tube 26 to a storage
3,025,579
Geoffrey iiittlewood, Sheffield, England, assignor to The
British iron and Steel Research Association, London,
England
CONTINUOUS CASTING OF METALS
Filed June 16, 1959, Ser. No. 820,744
Claims priority, application Great Britain June 17, 1958
1 Claim. ((11. 22--57.2)
tank 27, the latter tube 26 being of larger bore than the
tube 24. The piston 16 is mounted on the spring 18,
thereby supporting the mold 13.
Above and below the platform are two spaced limit
switches, such as micro-switches 2S and 29 respectively.
Switch 28, while operated by contact with the platform 14
prevents the valve 25 from closing, but on becoming in
operative through downward movement of the platform
This invention relates to improvements in continuous 10 14 (breaking contact with switch 28) causes the valve 25
casting apparatus.
to close, resulting in an immediate build up of pressure
US. Patent 2,815,551 describes a system of moving the
until the switch 29 is contacted by the platform 14 moving
mold used for continuously casting steel in such a manner
so as to prevent or minimize the effects of friction between
downwardly and causes the valve 25 to reopen.
water cooled and open at both ends and is used to solidify
ingot 12, which is being withdrawn by the withdrawal
When sticking of the ingot 12 to the mold 13 occurs,
the mold and the ingot. In this speci?cation the mold is 15 the mold 13 is drawn downward a short distance by the
or partly solidify the liquid metal which is poured in at
mechanism. Movement of the mold 13 and hence the
platform 14, causes the switch 28 to close the valve 25
ing or ingot at the other end.
which then prevents ?ow of the ?uid 19 from the cylinder
Frictional forces acting at or near the meniscus level in 20 17. The downward movement of the piston 16 is initiated
the mold often cause transverse tears in the ingot skin,
by movement of the platform 14 and mold 13 as caused
and said patent describes several methods of overcoming
by adhesion between the ingot and the mold wall. As
this tearing. One of these methods consists of supporting
soon as the contact between switch 28 and the platform 14
the mold on springs, so that when the ingot adheres to
is broken, closing the valve 25, the hydraulic ?uid entering
the mold wall, the mold is moved downwardly with the 25 the cylinder 17 will force the piston 16 downward at a
one end and withdrawn as a solid or partly solidi?ed cast
ingot and against the restoring force of the springs. When
the mold has travelled a short distance, a force is exerted
on the mold to move the-mold in the direction of ingot
withdrawal at a speed in excess of that of the ingot, so
that the friction causing the sticking is overcome by com 30
pressing the ingot skin, so inhibiting transverse ruptures.
This force is produced by mechanical or pneumatic means.
In the present application the compressive releasing
rate dependent upon the ?ow regulating position of the
metering valve 23. In accordance with the invention, the
rate of ?ow through the tube 24 will be su?icient to force
the piston 16 in a downward direction at a greater rate
than that caused by adhesion of the ingot to the wall of
the mold. Thus the mold will also move downward at a
greater rate than the ingot to break the adhesion therebe
tween.
force is applied by hydraulic means. Hydraulic means
The piston 16 moves downward under the force exerted
are preferred because they can produce a superimposed 35 by the hydraulic ?uid and compresses the spring 18 until
mold movement of uniform speed and almost instantane
the switch 29 reopens the valve 25. With the release of
?uid from the cylinder 17 through the line 26, the piston
ous acceleration, and thereby fully inhibit transverse rup
with platform 14 and mold 13 thereon will rise to its up
tures of the ingot skin.
per position with the platform again in its usual position
In accordance with the present invention, apparatus for
preventing tearing in ingots being cast by continuous cast 40 in contact with switch 28. ’When the friction between the
ing molds comprises a hydraulic system regulated by a
ingot and the mold again rises the cycle will be repeated.
control system which causes operation of the hydraulic
The storage tank 27 provides a means for containing ex
cess ?uid until such time as it is again required. The ?ow
system when sticking occurs, to move the mold faster than,
rate through the metering valve 23 may be kept in ad
and in the same direction as, the withdrawal of the ingot,
justment manually, or automatically in coordination with
and springs or like means being arranged, when permitted
by the control system, to act upon the mold to return the
the ingot withdrawal speed by well known electrical or
mold to its original position after the mold has passed
mechanical means.
through a predetermined distance.
It will be understood that the apparatus described
The invention will be more readily understood by way
should be duplicated in order that the vertical movement
of example from the following description, reference be 50 of the mold is maintained coaxial with respect to the ingot.
ing made to the accompanying drawing which is a part
However, it will also be understood the apparatus may
sectional and part diagrammatical view of the apparatus.
be applied by connecting one end of a lever to the piston
16 and attaching the other end of the lever to the mold
A stream of molten metal, as indicated at 11, is poured
into the open upper end of a water cooled mold 13 from
13, in which case only one cylinder would be necessary.
Alternatively, the use of springs such as 18 may be
suitable molten metal delivery means (not shown) with 55
dispensed with by admitting a continuous ?ow of hy
the casting or ingot 12 formed in the mold withdrawn
downwardly from the open lower end thereof by a with
draulic ?uid through the lower chamber of cylinder 17,
maintaining sufficient pressure therein just to hold the
drawal mechanism (not shown). The rate of molten
mold in its uppermost position. Upon the friction level
metal delivery to and the rate of ingot withdrawal from
the continuous casting mold 13 are coordinated for the 60 rising between mold and ingot, the mold will be moved
downward and so trip limit switches which will simul
proper solidi?cation of the molten metal.
A platform 14 is attached to the mold 13 and is con
nected at each end to a hydraulic means for lowering the
platform 14 and mold 13 when sticking of the ingot oc
curs. Only one such means is shown in the drawing and,
as there illustrated, comprises a piston rod 15 secured to
the platform 14 and attached to a piston 16 located in a
cylinder 17 which contains a spring 18 and a ?uid 19,
taneously: (1) Stop ?uid entering the lower chamber
of cylinder 17, (2) Stop ?uid leaving the top chamber 19.
Thus the mold will be forced down at a rate proportional
to the the rate of ?ow of ?uid which is controlled by
valve 23.
After travelling a certain distance, the valve 25 is
opened allowing fluid to ?ow out of chamber 19, and si
multaneously ?uid is re-admitted to the lower chamber
acting on opposite sides of the piston 16. The ?uid 19 is
continuously pumped into the cylinder 17 by a pump 22 70 to force the mold to its uppermost position.
In such a system, whereby the relative speeds of mold
from a storage tank 27 through a metering valve 23 in a
and ingot are not of great importance, so long as the
delivery tube 24 and is discharged through an electro
3
2,025,579
downward speed ofthe mold vexceeds that of the ingot,
the operating ?uid may conveniently be compressed air
and the system may be run from any available supply
of compressed air.
4
conduit means for the, discharge of said hydraulic ?uid
from said cylinder, a cut-off valve in said second con
duit means, and valve operating means for‘ closing said
valve when said mold initially moves downwardly from
an upper position against said spring means in response
to an increase in friction between said mold and ingot,
said valve operating means closing said valve to force
said mold downwardly at a substantially uniform rate
greater than the Withdrawal rate of said ingot, under the
While in accordance with the provisions of the statutes
I have illustrated and described herein the best form
and mode of operation of the invention now known to
me, those skilled in the art will understand that changes
may be made in the form of the apparatus disclosed with
out departing from the spirit of the invention covered 10 influence of the incoming ?ow of said hydraulic ?uid,
by my claims, and that certain features of my invention
said valve operating means being arranged to open said
may sometimes be used to advantage without a corre
valve after a predetermined downward movement of said
sponding use of other features.
mold to release hydraulic ?uid from said cylinder at a
What is claimed is:
?ow rate greater than said ?uid delivering rate and there
‘In apparatus for the continuous casting. of metal hav 15 by causing said mold to return to its said upper position
ing an upright open ended mold and means for deliver
at a substantially uniform rate under the in?uence of
ing molten metal to the upper end and withdrawing an
said spring means.
ingot from the lower end of said mold, the combination
References Cited in the ?le of this patent
comprising means guiding said mold for vertical move
ment in coaxial relationship to the withdrawn ingot in 20
UNITED STATES PATENTS
cluding a closed cylinder, a piston in said cylinder ar
1,743,367
Maybach ____________ __ Jan. 14, 1930
ranged to support said mold, spring means for supporting
2,815,551
Hessenberg et al. _____ __ Dec. 10, 1957
said piston in said cylinder, conduit means for continu—
ously delivering a hydraulic ?uid to said cylinder, a sec
ond conduit means of greater ?ow area than said ?rst 25
FOREIGN PATENTS
776,285
Great Britain ______ __.__ June 5, 1957
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